How an Engine Coolant Temperature Sensor Works
Internal combustion engines rely upon the use of a type of coolant to regulate operational engine temperatures. As its name would suggest, a vehicle’s coolant temperature sensor monitors the temperature of the coolant flowing throughout an engine. These functions include fuel metering, EGR operation, and fan engagement.
Where is the Engine Coolant Temperature Sensor Located?
Now, the thermostat housing is usually located on the cylinder head, close to the intake manifold. This part of the engine is designed to help regulate the circulation of coolant within your vehicle’s cooling system. So, it makes sense that the coolant temperature sensor would be placed close by. It’s the best spot for capturing accurate temperature readings from your coolant.
Keep in mind that some vehicles might have more than one coolant temperature sensor. In these cases, you’ll typically find one sensor near the thermostat housing, like already mentioned, and another one elsewhere, such as near the radiator or in the lower engine block.
This is to ensure that the engine control module (ECM) receives precise, real-time data on the whole system’s temperature fluctuations.
Causes of Sensor Failure
#1 – Low Coolant Level
One of the common reasons for a faulty coolant temperature sensor is a low coolant level. Suppose your coolant level is too low; it can cause air pockets to form in the cooling system, which leads to incorrect readings from the sensor.
In turn, this can affect the engine management system, resulting in issues like wrong fuel injection, poor fuel economy, and an overheating engine.
#2 – Air Pockets
As mentioned above, air pockets can lead to fluctuations in coolant temperature, which could cause erratic readings from the sensor. A cooling system flush might help eliminate the air pockets and improve sensor performance.
If you notice your cooling fans cycling erratically, one potential reason could be air in the system causing the sensor to send faulty signals.
#3 – Corrosion and Bad Connections
Over time, corrosion can build up on the engine coolant temperature sensor connections, causing a poor connection between the sensor and the engine management system. This weak connection can lead to incorrect readings and may trigger a trouble code.
#4 – Damaged Wiring and Connectors
Damage to wiring and connectors can also lead to a malfunctioning coolant temperature sensor. The coolant temperature sensor is connected to the engine management system using wiring and plastic hoses. If the wiring or connectors are damaged, this can cause incorrect readings from the sensor, and potentially even total failure of the sensor.
In these situations, it’s necessary to inspect all related wiring and connectors for damage and replace any damaged components.
Can You Drive With a Faulty Coolant Temp Sensor?
While a vehicle with a faulty coolant temperature sensor can often be driven from one location to the next, doing so is not advised. With time, many of the individual symptoms of a failing coolant temperature sensor can become problematic themselves.
An inoperable fan caused by a faulty coolant temperature sensor will quickly result in engine overheating. As a result, additional problems, such as head gasket leaks, can arise.
Likewise, abnormally high fuel rates caused by skewed data from a faulty sensor, can lead to the superheating and failure of a vehicle’s catalytic converter.
How to Diagnose a Bad Coolant Temperature Sensor
So, you’ve been noticing some weird stuff going on with your car’s engine temperature? Maybe it’s time to check out that coolant temp sensor. Don’t worry, diagnosing a bad coolant temperature sensor is something you can do. Let’s walk through it step by step.
#1 – Check Coolant Level
First things first, make sure your coolant level is good. You don’t want to misdiagnose a simple low coolant issue as a faulty sensor. Just pop the hood, locate the coolant reservoir, and check the level. If it’s low, top it off and see if your engine temperature issues persist.
#2 – Inspect Cooling Fans
Now, if your coolant level is fine, it’s time to check out the electrical cooling fans. These bad boys help keep your engine cool, and if they’re not coming on at the proper time, your engine temperature can skyrocket.
Start your engine and watch the cooling fans. If they don’t come on as expected, it might be the coolant temperature switch causing the problem.
#3 – Scan for Trouble Codes
Grab your trusty scan tool and connect it to your car’s OBD-II port. If you see one or more codes, take note of them and do some research on what they mean. These codes can help you pinpoint the issue.
At this point, if you suspect the coolant temperature sensor is the issue, you should consider having a mechanic take a closer look if you don’t feel confident in replacing the sensor yourself. The pros will have the proper tools and expertise to accurately diagnose and replace the faulty sensor if needed.
